the term float first originated as a misspelling of fleet, in an Age of Conquerors game, however it very quickly caught on.

since then it became the way to express whether a water had good fish (good float) or bad fish (bad float), whether someone was not going water at all (p3 no float). on land maps it is used in place of 'win' and 'do well' and just as a general good luck slogan.